Wednesday, January 20, 2010

... combat spacecraft would likely get around the same way the Apollo spacecraft went to the Moon and back: with orbit changes effected by discrete main-engine burns. The only other major option is a propulsion system like ion engines or solar sails, which produce a very low amount of thrust over a very long time. However, the greater speed from burning a chemical, nuclear, or antimatter rocket in a single maneuver is likely a better tactical option. One implication of rocket propulsion is that there will be relatively long periods during which Newtonian physics govern the motions of dogfighting spacecraft, punctuated by relatively short periods of maneuvering. Another is that combat in orbit would be very different from combat in "deep space," which is what you probably think of as how space combat should be – where a spacecraft thrusts one way, and then keeps going that way forever. No, around a planet, the tactical advantage in a battle would be determined by orbit dynamics: which ship is in a lower (and faster) orbit than which; who has a circular orbit and who has gone for an ellipse; relative rendezvous trajectories that look like winding spirals rather than straight lines.

Second, there are only a few ways to maneuver the attitude of a spacecraft around – to point it in a new direction...

This reminds me of how I understand sea battles were fought in the age of sail. Vessels at the mercy of the elements, wind (gravity for space ships), plotting long courses, sweeping in arcs towards each other, advantage gained by catching wind (or a lower orbit). Interesting to think of space Admirals in the future, memorising Nelson's tactics.